One enemy is too much.一个敌人也太多.
One eyewitness1 is better than ten hearsays.百闻不如一见。
One false move may lose the game.一著不慎，满盘皆输.
One false step will make a great difference.失之毫厘，谬以千里.
One father can support ten children, ten children cannot support one father.一个爸爸能扶养十个孩子，十个孩子却不可以赡养一个爸爸.
One father is more than a hundred schoolmasters.一个爸爸胜于一百个教师.
One flower makes no garland.一木不可以成林.
One foe2 is too many; and a hundred friends too few.朋友成百犹觉少，仇敌一人已嫌多.
One fool makes many.一人傻，傻大伙.
One foot is better than two crutches3.一只脚胜过两根拐杖.
One good head is better than a hundred strong hands.上百双有力的手，不如一个聪明的头脑.
One good mother is worth a hundred schoolmasters.一个好的妈妈顶得上一百个教师.
One good turn deserves another.以德报德.
One half of the world does not know how the other half lives.贫富不相知.
One has lived too near a wood to be frightened by owls4.深知底蕴，不以为怪.
One honest word is better than two oaths.两句誓词不如一句实话.
One hour today is worth two tomorrow.今天的一个小时抵得上明天的两个小时.
One hour's sleep before midnight is worth three after.午夜前睡一小时抵得上午夜后睡三小时.
One is never too old to learn.人没老得不可以学的时候。
One love drives out another.新爱逐旧欢.
One man makes a chair and another man sits in it.坐享其成.
One man may steal a horse while another may not look over a hedge.只许州官放火，不许百姓点灯.
One man, no man.个人是渺小的。
One mans fault is another mans lesson.一个人的过失是另一个人的教训。
One mans meat is another mans poison.一个人的美点，可是另一人的毒药。